Flavonoid pigments of butterflies in the genus Melanargia

Flavonoid pigments (18) were identified in the wings and body of Melanargia galathea: tricin, tricin 7-glucoside, tricin 7-diglucoside, tricin 4′-glucoside, luteolin, luteolin 7-glucoside, luteolin 7-diglucoside, luteolin 7-triglucoside, apigenin, apigenin 7-glucoside, orientin, orientin 7-glucoside, iso-orientin, iso-orientin 7-glucoside, vitexin 7-glucoside, vitexin 7-glucoside, isovitexin, isovitexin 7-glucoside and a novel but incompletely identified tricin 4′-conjugate. Examination of the wings and bodies of individual M. galathea, M. galathea var. procida, M. lachesis, M. russiae, M. larissa, M. occitanica and M. ines butterflies from a number of different populations in Europe by 2D PC revealed that variation in their flavonoid patterns was so minor that the flavonoid pattern of these Melanargia spp. may be considered constant. The concentration of flavonoids in the wings of each butterfly was greater than that in the body, as is the covering of scales. Not all flavonoids are located in the scales; some are also located in the reproductive tissues of the female. With the exception of the tricin 4′-conjugate which was absent from the egg and first instar larvae before feeding commences, these flavonoids were present in all the life stages of M. galathea. The presence of tricin 4′-conjugate in Melanargia but its absence from the larval food plants suggests that this compound is synthesized by the insect and that flavonoids are not merely sequestered from the diet but are also partly metabolized.     

Flavonoid glycosides from illuminated cell suspension cultures of Petroselinum hortense

Twenty-four different flavonoid glycosides were isolated from illuminated cell suspension cultures of parsley (Petroselinum hortense). The chemical structures of fourteen of these compounds were further characterized. The aglycones identified were the flavones apigenin, luteolin and chrysoeriol, and the flavonols quercetin and isorhamnetin. The flavones occurred either as 7-O-glucosides or as 7-O-apioglucosides, while the flavonols were 3-O-monoglucosides or 3,7-O-diglucosides. One-half of these glycosides were electrophoretically mobile and substituted with malonate residues.     

Flavonoids in Parahebe and Veronica: a chemosystematic study

Flavone glycosides are the main flavonoid leaf constituents in the related genera Parahebe and Veronica (Scrophulariaceae), in agreement with former chemical studies of the family. In Parahebe there are groups of species in which there are mainly luteolin glycosides, and groups in which 6-hydroxyluteolin dominates. Small amounts of apigenin occur in many taxa. Glycosylation is usually in the 7-position but 4′- and 5-glycosides were also found. In Veronica a larger variety of flavone aglycones was found: e.g. luteolin, apigenin, chrysoeriol, tricin and three different 6-hydroxyflavones. They are often present in the plants in the form of glucuronides. Glycosylation is in the 7-or-5-position. Most species of both genera have a distinctive pattern of flavonoid glycosides in their leaves which can be used for identification. Populations of P. catarractae are an exception in showing three different patterns, but here the variety in flavone profiles corresponds to the pattern of morphological and geographic variation within this taxon. Anthocyanins are responsible for the blue, mauve and pink colours of the flowers in the two genera. In Veronica they are based on delphinidin, whereas in Parahebe catarractae on both delphinidin and cyanidin.     

Flavonoid glycosides of Tribulus pentandrus and T. Terrestris

Twenty-five flavonoid glycosides were detected in Tribulus pentandrus and T. terrestris. The glycosides belong to the common flavonols, kaempferol, quercetin and isorhamnetin, with the 3-gentiobiosides as the major glycosides. Traces of a flavone (tricin) glycoside was also present in T. pentandrus. The separation of Tribulaceae as a distinct family from Zygophyllaceae is discussed.     

External and internal flavonoids from Madagascarian Uncarina species (Pedaliaceae)

External and internal flavonoids were isolated from 12 Uncarina taxa (Pedaliaceae), endemic to Madagascar. Four flavone aglycones, tricetin 7,3′,5′-trimethyl ether, tricetin 7,4′,5′-trimethyl ether, 5,3′-dihydroxy-6,7,4′,5′-tetramethoxyflavone and eupatorin were isolated from leaf wax of seven Uncarina taxa, Uncarina grandidieri, Uncarina decaryi, Uncarina abbreviata, Uncarina turicana, Uncarina platycarpa, Uncarina leandrii var. leandrii and Uncarina peltata, but not Uncarina stellulifera, Uncarina perrieri, Uncarina sakalava, Uncarina leptocarpa and U. leandrii var. rechbergeri. Furthermore, eight flavonoid glycosides were isolated from the leaves. Major glycosides were apigenin and luteolin 7-O-glucuronides and occurred in all the Uncarina taxa examined, except the absence of the former compound in U. peltata. Other glycosides were identified as hispidulin, jaceosidin, chrysoeriol and tricin 7-O-glucuronides, and luteolin 7,4′-di-O-glucuronide and a flavonol, isorhamnetin 3-O-diglucoside. From the results described above, methylated flavone aglycones and glucuronides were chemical characters of the leaves of Uncarina species, and also may be those of the family Pedaliaceae. Besides, an anthocyanin, two flavonols and three flavones were isolated from the flowers of U. grandidieri, and identified as cyanidin 3-O-rutinoside (anthocyanin), quercetin and isorhamnetin 7-O-glucuronides (flavonols) and apigenin, luteolin and jaceosidin 7-O-glucuronides (flavones).     

Species-specific kaempferol derivatives in ferns of the appalachian Asplenium complex

A series of kaempferol derivatives have been identified in fronds of three parental species of the Appalachian Asplenium complex. Asplenium platyneuron is characterised by the presence of the 7-glucoside of kaempferol 3,4′-dimethyl ether and also contains kaempferol 3,7-diglucoside, free and with an aliphatic acyl attachment. By contrast, A. rhizophyllum contains a remarkable caffeoyl complex of kaempferol glycosides, which appears to be chromatographically homogenous. However, on deacylation, the complex yields caffeic acid and the 7-glucoside, 3,7-diglucoside, 3-sophoroside-7-glucoside and 7,4′-diglucoside of kaempferol. Asplenium montanum, in addition to having previously characterised glycosylxanthones, has two further kaempferol derivatives. It has been confirmed that these various species specific flavonoids are inherited in an additive fashion in three interspecific hybrids.     

Negatively charged flavones and tricin as chemosystematic markers in the palmae

A survey of 125 species of the Palmae revealed a complex pattern of flavonoids in the leaf. C-Glycosylflavones, leucoanthocyanins and tricin, luteolin and quercetin glycosides were common, being present in 84, 66, 51, 30 and 24% of the species respectively. Apigenin and kaempferol were recorded in only a few species and isorhamnetin only once. Eighteen flavonoids were identified: the 7-glucoside, 7-diglucoside and 7-rutinoside of both luteolin and tricin, tricin 5-glucoside, apigenin 7-rutinoside, quercetin 3-rutinoside-7-galactoside, isorhamnetin 7-rutinoside, orientin, iso-orientin, vitexin, isovitexin and vitexin 7-O-glucoside. Many of the C- and O-flavonoid glycosides were present as the potassium bisulphate salts and negatively charged compounds were detected in 50% of the species. The distribution patterns are correlated with the taxonomy of the family in several ways. Thus, the Phoenicoideae and Caryotoideae have distinctive flavonoid patterns, there is evidence to support the separation of the subfamilies Phytelephantoideae and Nypoideae, and tricin is a useful marker at tribal level. At the generic level, Cocos is clearly separated from Butia, and other Cocoseae and Mascarena and Chamaedorea form well defined groups within the Arecoideae. A numerical analysis of these biochemical data, together with morphological characters, produces a new classification which suggests that the flavonoid data may have more systematic value than is indicated when they are applied to the traditional classification.     

Flavonoids from Artemisia ludoviciana var. ludoviciana

Nineteen flavonoids were isolated from Artemisia ludoviciana var. ludoviciana, including a new 2′- hydroxy- 6-methoxyflavone, 5,7,2′,4′-tetrahydroxy-6,5′-dimethoxyflavone. The known compounds include quercetagetin 3,6,3′,4′-tetramethyl ether, eupatilin, 5,7-dihydroxy-3,6,8,4′-tetramethoxyflavone, luteolin 3′,4′-dimethyl ether, jaceosidin, 5,7,4′-trihydroxy-3,6-dimethoxyflavone, tricin, hispidulin, chrysoeriol, kaempferol 3-methyl ether, apigenin, axillarin, eupafolin, selagin and luteolin together with three flavones which were previously isolated for the first time from Artemisia frigida: 5,7,4′-trihydroxy-6, 3′,5′-trimethoxyflavone, 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone and 5,7,3′,4′-tetrahydroxy-6,5′- dimethoxyflavone.     

Distribution of charged flavones and caffeylshikimic acid in Palmae

Identification of the phenolic constituents in flowers of nine palm species has revealed that charged C-glycosylflavones and caffeylshikimic acid are characteristically present. Flavonol glycosides are also common; the 3-glucosides, 3-rutinosides and 3,4′-diglucosides of quercetin and isorhamnetin and the 7-glucoside and 3,7-diglucoside of quercetin are all variously present. Tricin 7-glucoside, luteolin 7-rutinoside and several unchanged C-glycosylflavones were also detected. Male flowers of Phoenix canariensis differ from female flowers in having flavonol glycosides. As expected, in most species studied, flavonoid patterns in the flowers vary considerably from those found in the leaves.     

The leaf flavonoids of the orchidaceae

In a leaf survey of 142 species from 75 genera of the Orchidaceae, flavone C-glycosides (in 53%) and flavonols (in 37 %) were found to be the most common constituents. However, since these compounds are not found uniformly and their distribution shows a strong correlation with plant geography, it is not possible to represent the Orchidaceae by a single flavonoid profile. Thus, flavone C-glycosides are most common in tropical and subtropical species of the Epidendroid and Vandoid tribes (in 63%) and flavonol glycosides are more characteristic of temperate species of the Neottioid tribes (in 78%). By contrast 6-hydroxyflavones (in 6 species), luteolin (in 2 species) and tricin as the 5-glucoside (in 1 species) are all rare. Three new glycosides were characterised: scutellarein 6-methyl ether 7-rutinoside from Oncidium excavatum and O. sphacelatum, pectolinarigenin 7-glucoside from 0. excavatutn and Eria javanica, and luteolin 3′,4′-diglucoside from Listera ovata. The xanthones, mangiferin and isomangiferin were found in Mormolyca ringens, Maxillaria aff. luteo-alba and 5 Polystachya species and a mangiferin sulphate tentatively identified in P. nyanzensis. Other unusual phenolic constituents include 6,7-methylenedioxy- and 6,7-dimethoxycoumarins from Dendrobium densiflorum and D. farmeri, formed by the rearrangement during the extraction process from the corresponding O-glucosyloxycinnamic acids. The origin and relationship of the Orchidaceae to other monocot groups are discussed in the light of the flavonoid evidence.     

Flavonoids of Chrysosplenium tetrandrum

Chrysosplenium tetrandrum, from northern British Columbia, accumulates a variety of flavonoid glycosides. Several kaempferol and quercetin mono- and diglycosides were identified. The major flavonoid fraction consisted of O-methylated compounds having an hydroxyl or methoxyl substituent at position-6. Aglycones identified were 5,4′-dihydroxy-3,6,7-trimethoxyflavone, 5,6,7,3′,4′-pentahydroxy-3-methoxyflavone, 5,6,3′,4′-tetrahydroxy-3,7-dimethoxyflavone, 5,6,4′-trihydroxy-3,7,3′-trimethoxyflavone, 5,3′,4′-trihydroxy-3,6,7-trimethoxyflavone, and 5,4′-dihydroxy-3,6,7,3′-tetramethoxyflavone. All occurred as glucosides. The occurrence of 6-substitution and the preponderance of O-methylated flavonoids supports removal of Chrysosplenium from Engler's Saxifraginae.     

The taxonomic position of Sphaerocarpos and Riella as indicated by their flavonoid chemistry

The major flavonoid glycosides of Sphaerocarpos texanus are luteolin 7-O-glucuronide and 7,4′-di-O-glucuronide. Riella americana and R. affinis both contain apigenin, chrysoeriol and luteolin 7-O-glucuronides but R. americana additionally contains luteolin 3′-O-glucuronide. This finding supports the inclusion of Sphaerocarpaceae and Riellaceae in the order Marchantiales rather than their separation into another order.     

Flavone C-glycosides of two Metzgeria species

Six known tricin and apigenin di-C-glycosides, including 2″-O-ferulylisoschaftoside, have been identified in gametophytic material of Metzgeria conjugata. M. leptoneura contains a new di-C-glycoside, tricin 6-C-xyloside-8-C-hexoside. The chemotaxonomic relevance of the flavonoid patterns is briefly discussed.     

Flavonoid variation in the liverwort Conocephalum conicum: Evidence for geographic races

The flavonoids of 2 samples of Conocephalum conicum gametophyte tissue have been studied, one from U.S.A. and the other from Germany. Common to both samples were vicenin-2, lucenin-2, the 7-O-glucuronides of apigenin, chrysoeriol and luteolin and the previously unknown 7-O-glucuronide 4′-O-rhamnosides of apigenin, chrysoeriol and luteolin. Additionally the German sample contained the 7,4′-di-O-glucuronides of apigenin and luteolin and a new compound, apigenin 7-O-diglucuronide 4′-O-glucuronide. The North American sample contained, additionally, luteolin 7,3′-di-O-glucuronide, luteolin 7-O-glucuronide 3′,4′-di-O-rhamnoside (a new triglycoside) and 2 further derivatives of luteolin 7-O-glucuronide. Evidence is presented for the existence of geographic faces of C. conicum and for the qualitative invariability of the flavonoid patterns with changing season or environment.     

Flavonoid glycosides and the chemosystematics of Eucalyptus camaldulensisis

Leaf flavonoid glycosides of Eucalyptus camaldulensis were identified as kaempferol 3-glucoside and 3-glucuronide; quercetin 3-glucoside, 3-glucuronide, 3-rhamnoside, 3-rutinoside and 7-glucoside, apigenin 7-glucuronide and luteolin 7-glucoside and 7-glucuronide. Two chemical races were observed based on the flavonoid glycosides. These races correspond to the northern and southern populations of species growing in Australia. The Middle Eastern species examined were found to belong to the southern Australian chemical race. The major glycosides of E. occidentalis proved to be quercetin and myricetin 3-glucuronide.     

Flavonoids of the liverwort Marchantia foliacea

The major flavonoids of Marchantia follacea are the 7-O-β-d-glucuronides of apigenin, chrysoeriol and tricin, and apigenin-6,8-di-C-glucoside (vicenin-2). Minor constituents include the rhamnosylglucuronides of the above flavones. Apparent isomerization of the glucuronides on hydrolysis (MeOH-HCl) proved to be due to methylation of the sugar carboxyl group.     

Leaf flavonoid and other phenolic glycosides as indicators of parentage in six ornamental Fuchsia species and their hybrids

In a leaf flavonoid analysis of six Fuchsia species and seven Fuchsia hybrids, flavonols were found to be abundant in all taxa except F. procumbens. Flavone glycosides were found in only three species: luteolin 7-glucoside in F. splendens; and luteolin and apigenin 7-glucuronides and 7-glucuronidesulphates, tricin 7-glucuronidesulphate and diosmetin 7-glucuronide from one or both of the New Zealand species F. procumbens and F. excorticata. Luteolin 7- glucuronidesulphate is reported for the first time. Other less common phenolics identified include the flavanone, eriodictyol 7-glucoside from F. excorticata, a galloylglucose from F. triphylla, and a galloylglucosesulphate present in all taxa. Eight of the flavonoid glycosides proved useful as marker substances for particular Fuchsia species: quercetin 3- rhamnoside, 3-glucuronide and 3-rutinoside for F.fulgens; quercetin and kaempferol 3-galactosides for F. boliviana var. luxurians; diosmetin 7-glucuronide for F. excorticata and apigenin 7-glucuronide and 7-glucuronidesulphate for F. procumbens. The chemical results on the hybrids support the view that the cultivar ‘Mary’ is a hybrid of F. boliviana var. luxurians and F. triphylla and that both F.fulgens and F. triphylla are involved as parents of the cultivars ‘Koralle’ and ‘Traudchen Bondstedt’.     

Luteolin 7-glucuronide-3′-mono(trans)ferulylglucoside and other unusual flavonoids in the aquatic liverwort complex, Riccia fluitans

Thirteen flavonoid glycosides, including eight which are new have been identified in Riccia fluitans; aquatic and terrestrial forms of this plant have the same pattern. Luteolin 7-O-glucuronide-3′-O-mono(trans)ferulylglucoside is proposed as the type flavonoid for this species. Its absence from, and the presence of chrysoeriol in R. duplex, support the proposed separation of R. duplex from the R. fluitans complex. A micro-deacylation technique is described which can also be used for specific deglycosylation of luteolin glycosides at the 4′-hydroxyl.     

Biflavones of Dioon

Seven biflavones, amentoflavone, bilobetin, sequoiaflavone, ginkgetin, sciadopitysin, 7,4′,7′,4?-tetra-O-methylamentoflavone, and diooflavone (amentoflavone hexamethyl ether), were identified from extracts of the cycad genus Dioon. The biflavones were identified by direct comparison with authentic samples using m.m.p., co-chromatography in 3 solvents, and NMR studies of the acetates. This is the first time amentoflavone hexamethyl ether has been identified as a natural product. After surveying numerous species of the Cycadales, no evidence could be obtained for the occurrence of biflavone glycosides or of biflavones based upon any other nucleus than apigenin.     

Flavonoids in leaves and inflorescences of australian Cyperus species

A survey of the flavonoids of some 92 species of Australian Cyperus, mainly of subtropical or tropical origin, has confirmed a correlation previously reported in this family between flavonoid pattern and plant geography. The pattern found was similar to that of African and South American Cyperaceae, particularly in the occurrence of the rare marker substance, luteolin 5-methyl ether. Tricin and luteolin are relatively common, in glycosidic form, in the leaves while the flavonol quercetin is infrequent. When present, quercetin occurs either in glycosidic form or free as a methyl ether. The 3-monomethyl and 3, 7-dimethyl ethers of kaempferol and quercetin and the 3, 7, ?-trimethyl ether of quercetin are reported for the first time from the Cyperaceae. The flavonoid pattern of inflorescences is distinct from that of the leaves in that tricin is not detectable and that luteolin 5-methyl ether appears to be replaced by 7, 3′, 4′-trihydroxyflavone. In addition, the aurone aureusidin is more commonly present than in the leaves and is occasionally accompanied by two further aurones. The glycoxanthones mangiferin and isomangiferin occur rarely in all three species examined in the section Haspani, i.e. in C. haspan, C. prolifer and C. tenuispica. In general, however, the flavonoid data do not offer any markers which separate off different sections within the genus; there are, however, some significant correlations between the frequency of the flavonoid classes and subgeneric groupings.